Breastpump with Letdown Feature

ABSTRACT

Breastpumps and methods for use in extracting breastmilk, which can be used to generate, among other things, both a letdown or stimulation phase and a milk expression phase, are disclosed.

This application is a continuation of application Ser. No. 13/090,929filed on Apr. 20, 2011, which is a continuation of application Ser. No.10/413,463 filed on Apr. 14, 2003, now U.S. Pat. No. 8,282,596, which isa continuation-in-part of Ser. No. 09/475,681, filed Dec. 30, 1999, nowU.S. Pat. No. 6,547,756, and U.S. patent application Ser. No.10/114,686, filed Apr. 2, 2002, now U.S. Pat. No. 6,808,517, which is acontinuation-in-part of U.S. patent application Ser. No. 09/476,076,filed Dec. 30, 1999, all of which claim the benefit of U.S. ProvisionalApplication No. 60/170,070, filed Dec. 10, 1999.

FIELD OF THE INVENTION

This invention relates to breastpumps for drawing breastmilk, andparticularly to a breastpump whether operated manually or motorized, soas to produce both a stimulation, or a letdown phase, and an expressionphase.

BACKGROUND OF THE INVENTION

Breastpumps for use by nursing mothers are well known. They allow thenursing woman to express the breastmilk as necessary or convenient, andfurther provide collection of the breastmilk for later use. For somemothers, breastpumps may be a necessity, such as when the child hassuckling problems, or if the mother has problems with excessive ordeficient milk production, or soreness, deformation or injury of themammilla, or like conditions which are not conducive to manual breastfeeding.

Manual breastpumps are commonplace. They are relatively inexpensive andeasy to transport. Examples of such manually-driven pumps are in U.S.Pat. No. 6,497,677.

Electrically-driven breastpumps are also commonplace. They may be of asubstantially large size of a non-portable or semi-portable type,typically including a vacuum pump which has an electric motor that plugsinto standard house current. Besides eliminating the efforts of manualpumping, some advantages of this type of pump include bettercontrollability and regulation of the vacuum. The option of variablefrequencies (rates) and amplitudes (suction levels) is often provided.

Battery-driven breastpumps have also been developed. These breastpumpshave the advantages of controllability and regulation of the vacuum, aswell as being easily carried. Such a battery-driven portable breastpumpis described in U.S. Pat. No. 4,964,851, for example. This breastpump,sold under the name MINIELECTRIC by Medela, Inc., is lightweight andachieves good vacuum (i.e., negative pressure) regulation in preferredlimits, for example, between about 100 and about 220 mmHg. The LACTINAbreastpump sold by Medela, Inc. is also another type of breast pumpwhich may be driven by battery as well as house current. It is generallydisclosed in U.S. Pat. No. 5,007,899.

The prior art manual as well as motorized breastpumps have, toApplicants' knowledge, only been developed with a single type of “cycle”for a given pump. That is, the driving mechanism for generating thevacuum (negative pressure) to be applied at the breast in the moresophisticated pumps is geared to a particular sequence, or curve, ofnegative pressure increase (i.e., increasing suction), and then release.In these pumps, regardless of vacuum amplitude and frequency, theenvelope of the curve (vacuum over time) is essentially the same,barring unintended defects occurring at extreme settings. The curve isoften aimed at reproducing in some sense the suckling action of aninfant, for instance.

Breast pumping can cover a range of different conditions, however, suchas where the mother's nipples are sore for some reason, there is a stateof significant engorgement, some nipple stimulation may be particularlydesired, letdown and relaxation may be of particular interest, it may bedesired to increase milk production, and so on.

As noted above, some breastpumps provide the user with the ability tovary the amount of vacuum being applied, as well as the speed of thepumping action (i.e., number of vacuum cycles per minute). In someinstances, speed and vacuum level may influence each other, such that asspeed increases so does the vacuum level. The basic “curve” remainsfixed, however, as described above, and the user must adapt as best shecan to making variations within that particular curve built into themachine, which typically has been generalized for the overall populationof users.

Moreover, conventional breastpumps are not made to differentiate betweendifferent phases of the milk expression process, or equipped with amechanism or method of operation to accommodate the different phases.That process includes, for example, a period before breastfeeding,referred to as the milk ejection period, or “letdown”, in whicheffective removal of the milk from the breast is initiated by thesuckling action of a baby's mouth and jaw to produce or stimulate anejection reflex, in which stored milk is released and made available forgeneral expression. It is believed that efficient expression ofbreastmilk is improved by stimulating milk ejection before initiatingmilk expression.

“Letdown” is, of course, a well known phenomenon. The milk ejectionreflex is the neurohormonal reflex resulting from the tactilestimulation of the nipple sending neuronal impulses to the hypothalamus,and the neurohypophysial release of oxytocin into the systemiccirculation. The subsequent contraction of the myoepithelial cellswithin the breast caused by oxytocin moves milk from the alveoli intothe collecting ducts and forward to the nipple. Milk ejection, or themilk ejection period, is the interval when an increased availability ofmilk from the nipple is caused as a result of the stimulation of themilk ejection reflex. Milk ejection in women normally lasts forapproximately two minutes, but will, of course, vary from person toperson. The ejection reflex will be identified in the following also as“letdown” or “ejection”.

The level of pressure applied and the intermittency of the stimulationfor initiating ejection are different than the level and intermittencyof the action for actually expressing the breast milk. Conventionalbreastpumps do not provide a method or mechanism by which a user caneasily stimulate an ejection reflex and subsequently commence toefficiently express breastmilk.

A demand is therefore believed present for a breastpump that is usableto easily produce stimulation to initiate ejection, and in additionprovides efficient expression of breastmilk, thereafter by operationthereof.

SUMMARY OF THE INVENTION

It is a principal objective of the present invention to provide abreastpump including a mechanism that can be used to generate a letdownsequence. In one form, the breastpump further includes a plurality ofdiffering milk expression (extraction) sequences or curves, or changingcombinations of conditions over time, which effectively addressdifferent phases of breastmilk production. The invention in one formincludes a breastpump comprising a breastshield having a portion withinwhich a woman's breast is received for the expression of milk. One ormore sources of pressure change (e.g., vacuum) communicate with thebreastshield. The source(s) of pressure is operated so as to effectivelyelicit letdown and then a different phase of breastmilk production, suchas general milk expression.

The source of vacuum, in one embodiment, is operated manually, i.e., byphysically manipulating a pump mechanism of the manual breastpump withthe hand. The source of vacuum is operated by a motor drive or the likein another embodiment, with the motor drive being adjustable accordingto selections made by the user. In still another embodiment, the sourceof vacuum is operated by a motor, according to a controller with presetinstructions or user input instructions, and may automaticallytransition between different operating conditions according to thepreset instructions or operate according to a user's input, or both.

It will be understood that in each of the embodiments, there is amechanism for operating the source(s) of pressure change (e.g., vacuum)according to at least a first set of conditions and a second set ofconditions. While a negative pressure is typical for breastpumps, apositive pressure is also usable in some adaptations. For purposes ofthe present invention, one of the set of conditions corresponds to aletdown condition. The second set of conditions is at least one sequencefor pumping that is not for letdown, such as a general milk expressioncondition. A significant, and heretofore unavailable advantage realizedby the present invention is also the ready ability to modify thebreastpump suction action to a variety of desired generally expressionconditions, and provide this ability to the end-user.

In yet another aspect of the invention, an improved motorized breastpumpis provided which has a pre-programmed milk letdown sequence. Theletdown sequence is most advantageously made available through a button,switch or the like provided on the breastpump used to initiate thesequence. The present invention in another significant aspect has amanually generated letdown mechanism which is designed to be easilymanipulated to produce the staccato-like action considered advantageousto the ejection reflex.

These and other features and advantages of the present invention will befurther understood and appreciated when considered in relation to thefollowing detailed description of embodiments of the invention, taken inconjunction with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a manual breastpumpaccording to certain aspects of the present invention;

FIG. 2 is a side view of the breastpump of FIG. 1;

FIG. 3 is an exploded sectional view of the breastpump of FIG. 1;

FIG. 4 is a diagrammatic representation of the interaction of variouscomponents within a programmable breastpump according to anotherembodiment of the present invention;

FIGS. 5 through 8 are various methods (curves) for operating abreastpump to differing ends, FIG. 7 being a curve for a letdownsequence;

FIG. 9 is another representation of a letdown sequence;

FIG. 10 is a front view of an embodiment of a motorized breastpumpaccording to certain aspects of the present invention;

FIG. 11 is a rear view of the embodiment of FIG. 10; and

FIG. 12 is an exploded view of the embodiment of FIGS. 10 and 11.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION One embodiment ofthe invention is a manual breastpump as detailed in U.S. ProvisionalApplication No. 60/405,559 filed Aug. 23, 2002, incorporated herein byreference, and illustrated in FIGS. 1-3, depicted herein.

The breastpump assembly 110 includes a shield 112, for contacting thebreast. The shield 112 is attached to a conduit structure 114. A vacuumpump mechanism 116 is attached to the conduit structure 114. The conduitstructure 114 transmits vacuum generated in the vacuum pump mechanism116 to the shield 112 and transmits expressed breastmilk from the shieldto an attached container 118.

The shield 112 has a generally funnel shaped portion 120 shaped andsized for being received onto a breast. The shield 112 extends into asleeve 122 downstream from the funnel shaped portion 120. The sleeve 122is open so as to conduct expressed milk into the conduit structure 114.For purposes of the instant invention, the shape of the shield 112 andits formation with the conduit structure 114 are incidental; theparticular arrangement and details of these elements is in no waylimiting.

The conduit structure 114 is attachable to the shield 112 through ashield mount 124 sized and shaped to receive the sleeve 122. The conduitstructure 114 is generally a housing that interconnects and permitsfluid communication between parts of the breastpump assembly 110. Theconduit structure 114 connects to the sleeve 122, by way of the shieldmount 124 at the one end, and terminates with a valve mechanism as isknown in the art at a container end 126. The container end 126 mayinclude threads 128 or any suitable mechanism for releasable attachmentto container 118, which may be in the form of a milk bottle or the like.

The conduit structure 114 includes a first conduit 130 defined by aninner first conduit surface 132 for conducting expressed breast milkfrom the shield mount 124 through the valve mechanism and into thecontainer 118. The conduit structure 114 includes a receptacle 134 forreceiving the pump mechanism 116. The receptacle 134 may be a boreformed in the conduit structure 114 or a bore formed in a cylindricalextension (not shown) of the conduit structure 114. The receptacle 134further includes a longitudinal bore 138 in fluid communication with asecond conduit 140 for transmitting pressure changes generated in thepump mechanism 116 through the receptacle 134 and conduit structure 114.The second conduit 140 is in fluid communication with the first conduit130 in chamber 141 so as to conduct pressure changes through the conduitstructure 114 to the shield 112 and thence to a breast of a user.

The pump mechanism 116 is releasably and even rotatably attachable tothe conduit structure 114. The pump mechanism 116 includes two mainportions. A first portion is a substantially rigid shell or handle 142.The second portion is a flexible movable member in the form of adiaphragm-like structure 144 attached to the handle. The handle 142 maybe made of a rigid plastic similar to that of the conduit structure 114.Referring to FIG. 3 in particular, handle 142 has a central portion 146,which has the form of a dome or housing, and a bottom edge portion 148.The dome 146 includes an inner surface 150, which defines a vacuumchamber 152 with the diaphragm 144 as will be explained more fullybelow.

The handle 142 includes a first extension 154 in the form of a handleextending from a back side 156 of the handle 142, which is sized andshaped to be grasped by a hand or one or more digits of the user.Drawing the distal or first extension 154 toward the conduit structure114 and generally toward the user's body operates the first extension154 in one mode of operation of the breastpump. A second or proximalextension 158 extends from the front side 157, opposite the firstextension 154, in the form of a tab or smaller handle extension. Theproximal or second extension 158 may be smaller than the first 154 andmay be operated by drawing the extension downwardly toward the conduitstructure 114 in another mode of operation with a single digit of theuser, as described hereafter. Distal and proximal are used hereinrelative to the shield 112.

The diaphragm 144 includes two main parts. A first part is a flexibleportion 160, shaped like an inverted cup to be positioned inside thedome 146 of the handle 142 adjacent the inner surface 150 thereof. Theflexible portion 160 includes an outer edge 162 with a channel 164 fortightly fitting with the dome shell edge 148. The flexible portion 160is made of a naturally resilient material so that there is a tendencyfor the membrane to be resiliently returned to a starting position afterbeing deflected in use. The membrane 160 includes a central concavity180 on an upper surface thereof and a central opening to receive apuller 166. There is a thinned transition area 149 defining the middleof the flexible portion 160.

The second part of the diaphragm 144 is a rigid member or puller 166.The puller 166 includes a disc portion 168 and an extension or post 170.The disc portion 168 is a generally flattened oval member that iscentrally imbedded within or attached to the membrane 160 at the uppersurface concavity 180 and may be held in place by posts of the membrane160 inserted through holes arranged somewhat symmetrically around thedisc portion. The disc portion 168 includes a central opening 172 thatis open to the vacuum chamber 152 at an upper end thereof. The post 170is a hollow cylindrical member that is attached to the disc portion 168.A hollow bore 174 of the post 170 is aligned to be in communication withthe central opening 172 of the disc portion 168.

The extension 170 is sized and shaped to be received within the postreceptacle 134, via a press or interference fit. Preferably, theconnection of the extension 170 to the post receptacle 134 is releasableand rotatable or pivotable in the receptacle 134. In this manner, theentire handle 116 and extension 154 may be rotated to one side of thebreastpump assembly for the convenience of the user. In an alternateembodiment, the puller 166 may be fixedly connected to the conduitstructure 114. In yet another embodiment, the assembly 110 may be formedas a unitary unit. For ease of cleaning, it is preferred to provide thevarious elements of the assembly 110 as separate elements. Accordingly,for the purpose of this invention, the term connected may refer to areleasable or a permanent connection.

In one preferred embodiment, the lower end of the post 170 forms ahalf-lap feature 171, which when fitted to the receptacle 134 cooperateswith a converse feature 173 within the bore of socket 134 to limit thearcuate travel of handle 116 and prevent over-rotation.

In operation, at a rest position, which is a start or initial position,the pump mechanism membrane 160 lies against or closely adjacent to theinner surface 150 of the dome portion 146 of the handle 142. In thisposition, as shown in FIG. 1, the volume of the vacuum chamber 152 iszero or at a minimum volume. When the user manipulates the firstextension 154 by pulling the extension inwardly toward the conduitstructure 114, the post 170 and disc portion 168 remain connected to andmotionless with respect to the conduit structure while the handle 142moves with the extension. The rigid disc portion 168 pivots about apoint at a rear edge 176 thereof, causing the membrane 160 to pull awayfrom the inner surface 150 of the dome 146, which expands the vacuumchamber 152 a first volume to produce a first negative pressure therein.The reduced pressure is communicated through the central opening 172 ofthe disc 168, through the hollow bore 174 of the post 170, through thelongitudinal bore 138 of the receptacle 134, through the second conduit140 and thence the shield 112. Operation of the breastpump 110 by thismode of operation is intended to generate an amount of vacuum at acyclical rate in order to efficiently promote milk expression from abreast, i.e., general pumping. A very easily operated one-handed manualpump mechanism is thereby provided that operates a manual breastpump ina first mode of operation to produce an efficient expression of breastmilk Note also that the handle 142 freely rotates in receptacle 134,enabling the user to adjust the handle's position to a most convenientgrasping orientation.

When the user manipulates the second extension 158 by pulling thatextension downwardly (e.g., toward the conduit structure 114) in theother mode of operation, the membrane 160 pulls away from the innersurface 150 of the dome 146 at a distal region by pivoting about a pointat a front edge 178 of the disc, which expands the vacuum chamber 152 asecond volume to produce a second negative pressure therein.

The second volume may be less than the first volume so that a lesserrelative change in pressure is generated by this mode of operation ascompared to the one already described for general pumping. In thepresent embodiment, this difference may be due to the shape and travelof the first and second extensions 154, 158. That is, second extension158 travels a shorter distance before it is stopped by the hood mount124. First extension 154 has a longer distance of travel before it isstopped by the conduit structure 114. In an alternate embodiment (notshown), the depth of the vacuum chamber adjacent the second extension158 may be formed as to be greater than the depth of the chamberadjacent the first extension 154. When the pull of the puller 166 causesthe membrane 160 to pull away from the inner surface 150 of the dome146, a relatively greater change in volume is created in operation ofthe first extension 154 due to the greater depth of the resultantchamber as compared to manipulation of the second extension 158.

Operation of the breastpump 110 by manipulating the extension 158 inthis mode of operation is intended to generate an amount of vacuum(relatively less in absolute change) at a cyclical rate (which may berelatively more rapid) in order to efficiently promote a milk ejectionreflex, i.e., letdown. It can be seen that use of a small extension 158is possible and efficient to promote ejection due to the lesser amountof vacuum generated in the second mode of operation. Because of thelesser amount of force necessary the second mode of operation may occurrelatively more rapidly, which, it has been found, is desired to produceejection as compared to expression.

Another embodiment of the invention is a motorized breastpump having thecapability of producing vacuum and cycle frequency conditionscorresponding to at least a letdown sequence and some other sequence,such as an expression sequence. The breastpump may be preprogrammed todo so, or may be user programmable as detailed in U.S. Pat. No.6,547,756, incorporated herein by reference, or may have bothcapabilities. The breastpump may be operated according to the sequencesand parameters detailed in U.S. patent application Ser. No. 10/114,686,incorporated herein by reference. For purposes of the present invention,the actual general expression sequence used is not limiting, since aninventive concept is the combination of a letdown feature with anothersequence, such as generated by a general milk expression mechanism.

This motorized embodiment has the ability to program the breastpump withdifferent types of suction sequences, or cycles as they are sometimesreferred to herein. With reference to FIG. 4, for instance, thebreastpump utilizes a microprocessor-based system indicated at 60 whichis provided user input through a plurality of “chip” cards 61. Each chipcard contains one or more predetermined programs recorded on an EEPROM.For example, each card could contain a specific type of sequence alongwith a milk letdown sequence.

An EEPROM microcontroller of the type MB90562 may be used, for oneexample, or the Atmel 2-wire EEPROM chipcard microcontroller AT24C164for another. These provide about 16K of memory, which is consideredpresently sufficient.

The programs (some examples of which are described hereafter) arerecorded in a conventional manner, and would be provided to the motherready to use. The programmed chip card 61 engages an interface to themicroprocessor. The particular program on the selected chip card 61 isthen communicated to the microprocessor 60. Microprocessor 60 isintegrated with the drive unit 25 to effect operation of the drive unitin accordance with the selected program, drawing upon either the ACpower source as converted via standard technology to DC (indicated at 68in FIG. 4), or from the battery source 39. The microprocessor 60 canalso control power management.

One embodiment contemplated provides a milk letdown sequence (milkejection reflex) that can be engaged without need of a chip card for thesame. The milk letdown sequence (described below) is pre-programmed inthe microprocessor 60, or may otherwise be wired into the circuitry in amanner to override the then-existing operating program. When the motherdesires to engage this sequence, she presses the button 49, whichproduces and sends an electrical signal, as to the microprocessor 60.The letdown program is then caused to be effected.

It will be readily understood that a chip card 61 is but one way toprogram the microprocessor 60. Other input means could be used, such asmore dedicated buttons like button 49, each set to actuate a givensequence pre-programmed into the microprocessor 60. A numeric pad couldbe provided to input a code. The programs could be provided through anelectronic data link, such as a modem, or optically, or otherwise.Furthermore, the microprocessor may be provided with the capability toautomatically transition from one sequence or cycle type to another andoptionally to a third or more cycle types without input from the user.

It can thus be seen that a variety of different suction cycles orsequences can now be provided with the same breastpump equipment. Anexample of the kind of methods that such cycle could represent comprisesFIGS. 5 through 9.

FIG. 5, for instance, is what is referred to by Medela, Inc. as the“Standard Classic Program”. This is a method for operating a breastpumpthat has been developed which is considered to provide a general optimalsuction curve reminiscent of an infant's normal suckling, such asprovided by the 015 “CLASSIC” breastpump sold by Medela, Inc. Asindicated in the graph of FIG. 5, negative pressure is along the y-axis(in millimeters of mercury) and time (in seconds) along the x-axis. Inthis particular method, the cycles are fixed at about 47 per minute; theamount of suction is generally adjustable between about 100 to about 250mmHg.

FIG. 6 illustrates what can be termed as a new “Sore Nipple Program”method. In comparison to FIG. 5, it will be seen that the lower end ofthe vacuum range is reduced to about 20 mmHg, and the overall suctioncycle is extended in duration, i.e., from a low of about 25 cycles/min.to about 40. For a lower vacuum applied in this program, there is anincrease in the number of cycles. In general, however, there is a slowerand gentler suction compared with the “CLASSIC” program of FIG. 5.

FIG. 7 shows a new method for operating a breastpump which is consideredto yield an increase in milk output. This is a letdown sequence. This isalso a program that might be applied between regular pump sessionsseveral times a day. In this method, the breastpump is operated at arapid cyclical rate on the order of about 120 cycles/min., preferablywith a pause after a period of vacuum application; here, 10 seconds ofvacuum, then a 2 second pause. The negative pressure is in the range ofabout 50 to about 150 mmHg. Note the detail in the inset of FIG. 7showing the rapidity and steep slopes of the vacuum application.

What has been termed a new “Superior Program” for operating a breastpumpis illustrated in FIG. 8. A vacuum range of about 100 to about 250 mmHghas been chosen, with cycles ranging from about 47 to about 78 perminute. The cycle rate and the vacuum are tied, such that as, forinstance, the cycles decrease, the amount of vacuum increases, i.e.,there is an inverse relationship. It will be noted that this programdiffers from the “CLASSIC” program above in part through a sequence thatinitially reaches a peak negative pressure, then smoothly starts apressure increase (less negative) along a similar (although opposite)slope to that of the negative pressure build-up, but then slows thepressure increase briefly, before continuing on essentially the initialslope for the negative pressure release. A milk letdown sequence is alsoincorporated in this “Superior Program,” and utilizes a vacuum range ofabout 50 to about 150 mmHg, with cycles ranging between about 80 toabout 160 per minute.

A preferred vacuum cycle for stimulating the milk ejection reflex bygenerating a rapid cyclical pressure change with a breastpump is shownin the graph of FIG. 9. The graph includes two separate curves, but withthe same envelope or overall pattern. A first curve C, which ranges inpressure from 0 mmHg (atmospheric) to about −45 mmHg (vacuum), theminimum curve C, represents the lower limit of the range of the vacuumcycle (lower amount of peak vacuum). A second curve D, which ranges inpressure from 0 mmHg to about −225 mmHg, the maximum curve D, representsthe high limit of the range of the vacuum cycle (highest amount of peakvacuum). The minimum and maximum curves C, D differ in amplitude andshare an envelope.

It can also be seen from the graph of FIG. 9 that the time duration ofeach of the minimum and maximum cycles C, D does not vary with theamplitude of the vacuum. In other words, in a curve cycle where the peakamplitude of the vacuum is greater, the time duration of the entirecycle is the same as that of curve having a lesser peak amplitude. Inthe illustrated cycle, the time duration of the cycle remains at 0.5seconds whether at the minimum or maximum range of vacuum operation. Inone preferred embodiment, no rest period is provided between cycles.Accordingly, the frequency of operation of the breastpump remains atabout 120 CPM, since there is no pause between cycles in the preferredembodiment. In another embodiment, a rest period of 0.0 to 0.5 secondsis provided between vacuum cycles.

FIGS. 10-13 show a motorized breastpump 10′ with a handle 12′. In thisembodiment the breastshields 17 are stored or carried in a holder 26mounted to the back of the unit. FIG. 11 shows the rear of thebreastpump 10′ wherein the breastshields are attached to respectivecontainers 18, which are stored in holder 26.

FIG. 12 shows internal workings of the motorized breastpump of FIGS. 10and 11. Breastpump casing 10′ has a drive unit 25 mounted therein. Thereare, of course, any number of drives that may be used for diaphragmpumps such as those used in the instant embodiment. Indeed, the type ofpump (diaphragm, piston, etc.) is not significant to certain aspects ofthe present invention. The driving mechanism for the breastpump shownfor the embodiment in point, however, is a linear drive for thediaphragm pumps consisting of a reduction drive arrangement and a 12 VDC-motor 28.

The drive 25 may be controlled according to the arrangement shown inFIG. 4, with a power supply (e.g., batteries) 39 positioned in lowerhousing part 13, which provides power to drive 25 according to amicroprocessor 60 positioned upon board 60′. The breastpump 10′ includesa cover 35″ and shells 24′ for the diaphragm pump 30. The shells 24′ aremounted in a removable manner in the upper housing, as through a snapfit or interference engagement, to allow easier access for cleaning orreplacing the membranes 36 of the pumping mechanism, and for cleaningthe shells themselves. Diaphragm members 34, may be made of any suitablydurable flexible and durable fluid-impervious material (to be airtight),such as silicone with a Shore A hardness in the range of 30 to 70. Themembrane and shell are in substantially airtight engagement.

When the membrane 34 is pulled away from the shell, a vacuum isgenerated in the space between the shell interior and the membrane,which is connected via tubing connected to outlet part 31 to communicatethe vacuum to a respective breastshield 17.

Prophylactic (protective) disposable/cleanable covers 36 areadditionally and advantageously provided, which form-fit over thediaphragms 34 and isolate them from air and other fluid from thebreastshields. The covers 36, which can be made of the same material asthe membranes but thinner, are likewise fluid-impervious.

As shown in detail above, the microprocessor operates to control thedrive unit 25 and, thereby pump mechanism 30, to produce pressureconditions to address different sequences of operation according to thepresent invention.

Again, more detail on this motor-driven embodiment can be gleaned fromthe priority document referenced above.

Thus, while the invention has been described herein with relation tocertain embodiments and applications, those with skill in this art willrecognize changes, modifications, alterations and the like which stillcome within the spirit of the inventive concept, and such are intendedto be included within the scope of the invention as expressed in thefollowing claims. For one example, the manually operated letdownmechanism could be a collapsible button-like device manipulated byfinger pressure on a dome-shaped member to collapse the dome, which thenrapidly returns to its original shape to be pressed again. The smallpressure change (either positive or negative) is communicated to thenipple, and perhaps some surrounding area of the breast. Further variousdevices, in order to yield the letdown sequence, whether applied to amanual pump or otherwise, need not be a part of the breast shield itselfor in close proximity thereto, as shown in the motorized embodimentdescribed herein. The pressure source could further be a single sourceor plural sources, such as one for letdown and one for general milkexpression. One source could be manually driven, while the other ismotor-driven.

1. (canceled)
 2. A breastpump comprising: a breastshield having aportion adapted for receiving at least part of a woman's breast; asource of vacuum adapted for communication with said breastshield tocyclically deliver vacuum to said breastshield; and a controlleroperatively connected to said source of vacuum, said controller beingprogrammed to operate at least said source of vacuum according to apre-set sequence constituting rapid cycles per minute in a manner thatis specifically implemented so as to result in a milk ejection reflex(letdown) prior to milk expression, and then operate according to aslower sequence of fewer cycles per minute than said letdown sequencedin a manner that is specifically implemented so as to provide generalmilk expression, wherein the maximum level of vacuum in saidbreastshield during said milk expression sequence is greater than themaximum level of vacuum in said breastshield during said letdownsequence.
 3. The breastpump of claim 2 wherein said vacuum is a partialvacuum.
 4. The breastpump of claim 2 wherein said source of vacuumincludes at least an expansible chamber device and a motorized drivesystem.
 5. The breastpump of claim 4 wherein said expansible chamberdevice comprises a diaphragm pump.
 6. The breastpump of claim 2 whereinsaid source of vacuum is includes a motor operatively connected to saidcontroller, and wherein a first motor drive operation is designedspecifically to yield said pre-set sequence specifically implemented toproduce a milk ejection reflex when initiated.
 7. The breastpump ofclaim 6 wherein said first motor drive operation is initiated by aswitch operatively connected to said controller.
 8. The breastpump ofclaim 7 wherein said switch is a button that is operable by a user. 9.The breastpump of claim 2 wherein said source of vacuum includes a motoroperatively connected to said controller, and wherein a second motordrive operation is designed specifically to yield said sequence that isspecifically implemented so as to provide general milk expression wheninitiated.
 10. The breastpump of claim 2 wherein the controller isfurther programmed to operate at least said source of vacuum totransition between said milk letdown sequence and said milk expressionsequence.
 11. The breastpump of claim 10 wherein transitioning betweensaid milk letdown sequence and said milk expression sequence is actuatedby a user-operated input device operatively connected to said controllerthat sends a signal to said controller to actuate said milk letdownsequence or said milk expression sequence.
 12. The breastpump of claim10 wherein the controller is further programmed to operate at least saidsource of vacuum to automatically transition between said milk letdownsequence and said milk expression sequence.
 13. A breastpump comprising:a breastshield having a portion adapted for receiving at least part of awoman's breast; a source of vacuum adapted for communication with saidbreastshield to cyclically deliver vacuum to said breastshield; aprocessor operatively connected to said source of vacuum to control saidsource of vacuum; and a memory including executable instructions that,when executed by said processor, cause at least said source of vacuum tooperate according to a pre-set sequence constituting rapid cycles perminute in a manner that is specifically implemented so as to produce amilk ejection reflex (letdown) prior to milk expression, and thenoperate a slower sequence of fewer cycles per minute than said letdownsequenced in a manner that is specifically implemented so as to providegeneral milk expression, wherein the maximum level of vacuum deliveredto said breastshield during said milk expression sequence is greaterthan the maximum level of vacuum delivered to said breastshield duringsaid letdown sequence.
 14. The breastpump of claim 13 wherein saidvacuum is a partial vacuum.
 15. The breastpump of claim 13 wherein saidsource of vacuum includes at least an expansible chamber device and amotorized drive system.
 16. The breastpump of claim 13 wherein saidsource of vacuum includes a motor operatively connected to saidprocessor, and wherein a first motor drive operation is designedspecifically to yield said milk letdown sequence when initiated.
 17. Thebreastpump of claim 16 wherein said first motor drive operation isinitiated by a switch operatively connected to said processor.
 18. Thebreastpump of claim 17 wherein said switch is a button that is operableby a user.
 19. The breastpump of claim 13 wherein said executableinstructions, when executed by said processor, cause at least saidsource of vacuum to transition between said milk letdown sequence andsaid milk expression sequence.
 20. The breastpump of claim 19 whereintransitioning between said milk letdown sequence and said milkexpression sequence is actuated by a user-operated input deviceoperatively connected to said processor that sends a signal to saidprocessor to actuate said milk letdown sequence or said milk expressionsequence.
 21. The breastpump of claim 19 wherein said executableinstructions, when executed by said processor, cause at least saidsource of vacuum to automatically transition between said milk letdownsequence and said milk expression sequence.